A separate analysis is designed to examine the incidence and effects of hypopituitarism after MTBI. The incidence of hypopituitarism after MTBI is not known. However, in patients who have persistent symptoms at one year post-injury, 35% have been found to have deficiency one or more pituitary hormones. The clinical characteristics, MRI imaging results, EEG and MEG results of the patients who have pituitary deficiency will be compared to those of patients with normal pituitary function. The relationship between pituitary dysfunction and functional outcome, cognitive recovery, and resolution of PCS will be examined as well.